Continuous backup or continuous data protection involves capturing every version of the data that a user saves. In effect, computer data is backed up by automatically saving a copy of every change made in the data. The administrator can then use the backup files to restore the data, if required.

Continuous data protection services save any changes made in the data in a separate data location. Different methods and technologies are available that can be used to capture the continuous changes that are made in the data. These solutions can be used to backup images, mail boxes, messages, files, logs and database files.

The difference between continuous data protection and traditional data backup is that there is no need to specify the time for backing the data. As the name suggests, it is continuous. A traditional data backup, on the contrary, can save data only to a point at which the last data backup was taken.

When continuous data protection is being done, there are no backup schedules. Every time data is written to a disk, it is asynchronously written to a second location, by means of a network. This process eliminates the need for scheduling backups every night, but it involves some overheads for writing data to disk. True continuous data protection solutions allow users to restore systems at any point of time.

Some services, which are sold as continuous data protection, only allow users to restore the systems at fixed intervals, like 1 hour ago or 24 hours ago. These services are often called snapshot based solutions.

Experts have different opinions about the granularity of backup needs. Some people feel that continuous data protection is a must. This is also the view of the Storage Networking Industry Association. Others feel that it is sufficient to capture the data every few seconds.

RAID, replication or mirroring provides protection from storage hardware failure by protecting the most recent copy of the data, whereas continuous data protection has the capacity to restore earlier versions of the data also.

In some cases, continuous data protection may require less space on the disk than traditional backup solutions. This is because most continuous data protection solutions save changes at the byte or block level, rather than at the file level.

What this means is that if you change one byte out of a large file, only the changed byte or block will be backed up, whereas traditional incremental or differential backups involve making copies of entire files.

Trackback URI | Comments RSS